of the Cornish FisJierinen. 173 



microscope, shows that it is composed of innumerable plates, an 

 object of great beauty ; these plates effervesce with acid, and so 

 do the plates of the mouth and tips of the processes. 



When the softer parts of the feelers are cut transversely, they 

 are composed of fine tubes, and when magnified have very much 

 the appearance of some of the corals. The animal is covered with 

 a dark slimy mucilaginous skin, which peels ofi" freely ; under- 

 neath this it is light gray, and has a reticulated appearance, re- 

 sembling bird^s-eye maple. They are of various sizes and lengths, 

 often nearly a foot in length and thick in proportion ; they some- 

 times draw themselves almost into a ball, at others are much 

 inflated in the centre. At times they lie motionless, but generally 

 they are in motion. So much for the external appearance. 



The jaws are composed of five strong calcareous plates, to these 

 the tentacula are attached, and from the under side in the inte- 

 rior of the animal extend five broad muscles, which reach the 

 whole length. These are again held together by a great number 

 of smaller ones placed transversely, until nearly reaching the 

 lower part, when they are diagonal, no doubt for the pm'pose of 

 closing the opening at the opposite end to the mouth. 



They eat portions of dead fish, shells, &c. (I have reasons for 

 believing Terebella) . I have found in their intestines a Buccinum 

 incrassatum, with the animal in it, portions of Balani, Echini, 

 Nullipora, sand, &c. The faeces are thrown out with a jerk, and 

 are of an oblong-oval shape, strung together like the eggs of a 

 snake, and are of a dark mud-colour. 



There is one circumstance connected with these things of in- 

 terest, — they are enveloped in a film so tenacious that it is a dif- 

 ficult matter to rub them to pieces in the water j on exposure to 

 air they lose their tenacity and crumble to pieces. The circum- 

 stance I allude to is, that this tenacious covering will explain in 

 some measure the preservation of the coprolites of the ancient 

 Saurians found in the blue lias ; for in all probability they were 

 enveloped in a similar tenacious covering. 



In Professor Forbes^s work there is a question how the water 

 which is found in the interior enters. If I understand it right 

 this is a doubtful matter ; probably the following may in some 

 measure explain it: — Theyraise the opening at the opposite end to 

 the mouth, open it wide, and I expect create a vacuum ; the water 

 then flows into it freely. After a short time they close this, and 

 by a muscular motion it may be observed as if passing towards 

 the head. This taking in the water is repeated several times 

 with short intervals, and after a little rest the whole of the water, 

 by the same orifice, is thrown out in a continuous stream. It 

 then commences again to take in more. 



It is extremely irritable, and on being touched or disturbed, 

 throws out a bunch of white tapered threads about an inch in 



